A research team from the Icahn School of Medicine at Mount Sinai published the first controlled evidence showing that an intranasal ketamine spray conferred an unusually rapid antidepressant effect – within 24 hours — and was well tolerated in patients with treatment-resistant major depressive disorder. This is the first study to show benefits with an intranasal formulation of ketamine. Results from the study were published online in the peer-reviewed journal Biological Psychiatry. "One of the primary effects of ketamine in the brain is to block the NMDA [N-methyl-d-aspartate] glutamate receptor," said James W. Murrough, MD, principal investigator of the study, and Associate Professor of Psychiatry and Neuroscience at the Icahn School of Medicine at Mount Sinai. "We found intranasal ketamine to be well tolerated with few side effects," said Kyle Lapidus, MD, PhD, lead author of the study, and Assistant Professor of Psychiatry, at the Icahn School of Medicine at Mount Sinai. “We hope to see this line of research further developed so that we have more treatments to offer patients with severe, difficult-to-treat major depressive disorder,” said Dennis Charney, MD, study co-author, and Anne and Joel Ehrenkranz Dean of the Icahn School of Medicine at Mount Sinai, and President for Academic Affairs of the Mount Sinai Health System.